Variable environment, scale-able, roll to roll process/apparatus for manufacturing thin film electronics on flexible substrates

ABSTRACT

A roll to roll, thin film manufacturing process/apparatus overcoming the shortcomings of current roll to roll processing; The roll to roll enabled cartridge is loaded with a bolt of flexible substrate. A skate couples with a cartridge, forms a seal with the cartridge&#39;s bottom aperture and drives the cartridge along a rail to an array of deposition heads. System control commands a head to mate with the cartridge top forming a seal about the variable area deposition aperture. The mating of the skate, cartridge and head form a pressure vessel wherein a film forming environment may be maintained. As the substrate advances through the deposition zone a layer is formed, bolt end to bolt end. Device growth continues from one head to another, as grown device encapsulation seal inclusive, aperture environmental seals applied, labeled cartridge is routed to dock, skate returns to process start.

We hereby claim the priority date of our provisional utility application No. 60/850,760 date Oct. 10,2006.

FIELD OF THE INVENTION

The present invention generally relates to roll to roll process manufacturing of thin film electronics on flexible substrates. Specifically it relates to pressure enabled enclosure-based manufacturing of thin film electronics on flexible substrates providing for a plurality of layer formation and virtually any method of layer deposition, formation.

BACKGROUND OF THE INVENTION

In seeking a way to manufacture (via roll to roll processing) highly efficient very low cost organic photovoltaics, organic light emitting diode arrays, organic thin film transistor arrays, thin film transistor arrays, etc, the realization was made that the invention could manufacture virtually all flexible substrate based thin film electronics.

SUMMARY OF THE INVENTION

The present invention has been made in view of the lack within the industry of a pressure vessel that robustly enables versatile roll-to-roll processing of thin film electronics on a flexible substrate. The object is to provide a pressure vessel that enables not only roll to roll processing but also provides for scale-able configurations for assembly-line production facilities for the ubiquitous manufacture of said electronics. The core aspect of the invention provides a pressure vessel for applying varying pressure working processes for the formation of a plurality of device layers on the flexible substrate via multiple roll to roll sequential, non sequential processing steps or hybrids of these. Moreover the cartridge component of the pressure vessel allows for substrates to be loaded, conveyed, processed, sealed, stored and transported in a single container.

BRIEF DESCRIPTION OF THE DRAWINGS (FIGURES)

FIG. 1: the Process/Apparatus

FIG. 2: some Components, a larger view of the rail, skate, cartridge and head

FIG. 3: Process/Apparatus Elevation

SPECIFICATION, DETAILED DESCRIPTION OF THE INVENTION

The Process/Apparatus

( FIG. 1) a cartridge 3 is loaded with a fresh bolt of flexible substrate 5 via the cartridge door. The bolt is placed on one of the axles or spindles concentrically mounted in the end wall of each cylindrical lobe of the cartridge. These lobes are joined by a continuous web forming a hollow sheath. The substrate is fed through this sheath passing between both top and bottom apertures and fixed via an auto-clamping mechanism to the axle in the adjacent cylinder. Thus the substrate is readied for roll to roll action. System control causes the skate 2, mounted on the rail 1, to couple with the cartridge via the aperture in the bottom web of the sheath forming a pressure seal and then moves this assembly along the rail to a station 6, aligns the cartridge's variable area aperture deposition or film formation window (located on the top web of the cartridge) with a head 4. System control then commands the head to mate with the top surface of the cartridge forming a pressure seal around the deposition aperture. System control then initiates and maintains a pressure regime within the head, cartridge, skate formed pressure vessel (FIG. 3: 2, 3, 4) and controls substrate feed rate and layer forming through the deposition zone. Axle hub mounted electromechanical rotational drives or skate mounted geared arms cause the roll to roll action within the cartridge. System control initiates and maintains head specific layer deposition/formation. This layer deposition is applied from one bolt end to the other. Upon completion of a device layer said pressure vessel is flushed of any potential contaminants and declared contaminant free by the flushing gas's exit stream particle count. The device growth continues as system control first decouples the skate/cartridge assembly from the head and aligns the skate/cartridge assembly with the next head. This alignment is performed by rotating the skate/cartridge assembly or driving this assembly to the next head. This head is devoted to the formation of the next layer. The process continues through as many heads and stations ( a linear or radial array of layer specific heads) as needed to complete the device and apply it's encapsulation (hermetic sealing). Once the device is completed the top and bottom apertures on the cartridge are closed, environmentally sealed, the cartridge labeled and routed to it's dock. The skate returns to the start of the line to re-initiate.

Primary Process Components

A) The Rail: (FIG. 2:1) a hollow (circular in cross section) structural, supporting member which is the process backbone and road for advancing the process from station to station and so head to head. Internal to the rail are communication and control lines as well as conductors (rotating, slip rings or patches) for powering the process and waste energy recycling. Any rail patch conductors are on the outer surface of the rail and penetrate through the rail wall and into the interior of the rail to continue their conduction path internally. System communication and control lines are present.

B) The Cartridge: ( FIG. 2:3) a structural enclosure, pressure tolerant (from less than or equal to 0.1 Torr vacuum through ambient and on into positive pressure ranging up to 200 or more PSI) with two adjacent cylindrical lobes with axles or spindles concentrically located in each, allowing the roll to roll bi-directional (to and fro) uptake/feed action of the device substrate through the deposition zone. The adjacent lobes of the cartridge are joined by top and bottom webs forming the previously mentioned sheath. The top web has a variable area aperture deposition/film formation window. The bottom web has an aperture which may have the same fixed dimensions as that of the top aperture and is parallel and coaxial to the top aperture. The distance between top and bottom apertures is the gap (sheath) through which the flexible substrate feeds. The pressure resistant door provides for loading fresh substrate bolts and the safe removal of fully grown devices. Substrate sensitive, auto-adjusting substrate guides are an implicit feature of the cartridge. Pressure resistant electromechanical drive or mechanical rotational drive interfaces exist incorporated into the walls of the cartridge at each axle hub. Hypo-hyperbaric valves and an array of process and quality control sensors completes the cartridge.

C) The Skate: (FIG. 2:2) In one embodiment acts as a robot, semi-autonomous to system control and provides for cartridge drive from point to point. Carries computer control algorithms and data for a given device's sequential growth. Contains, supports and controls the cold-plate/thermoelectric heat sink (TCP) across which the flexible substrate feeds maintaining the substrate at constant temperature. The TCP is mounted on the skate. The TCP consists of a highly thermally conductive plate in conjunction (direct contact) with parallel thermoelectric semiconductor plates which upon receiving the heat conducted through the cold-plate convert this heat to direct current (DC) electricity. The TCP's energy conversion capacity may vary as needed by layer forming requirements by adding or subtracting thermoelectric semiconductor plates. Any patch conductors will reside on the inner surface of the partially coaxial ( to the rail) skate structure, thus in intimate, electrically conductive contact providing for the recycling of this DC.

D) A Head: In FIG. 1 a generic head 4 is configured to mate with the cartridge 3 top's variable area deposition aperture, forming a pressure seal. Each head has a hollow telescoping stem such that a sealing force may be applied to the cartridge's mating surface (FIG. 3:4). The hollow stem allows for material feed and process and quality control. A generic head may contain any product/device, layer specific, forming apparatus. Certain portions of certain heads must functionally withstand temperatures greater than or equal to 600 degrees Celsius. Any head may be equipped with vacuum/pressure pumps, valves required to maintain system pressure at any required level. Additionally neat gas sources may be present as well as system and quality control elements

E) The Station: (FIG. 3:6) a radial or linear array of heads where each head is devoted to the formation of a particular device layer. 

1) A variable pressure, scale-able, roll to roll manufacturing process/apparatus for the ubiquitous manufacture of thin film electronics on flexible substrates is claimed, this apparatus/process works by using these process components in the way and order described: the Cartridge; consists of two parallel cylindrical lobes, each with a spindle or axle and hub concentrically mounted in the capping end wall of each lobe, these two lobes are joined by a continuous web which forms a hollow sheath, a virgin bolt of flexible substrate is loaded onto an axle via the pressure enabled cartridge door, the leading end of the bolt is fed through the sheath and fixed via an auto-clamping system to the axle in the adjacent lobe, the Skate mounted on the Rail couples with the cartridge via the fixed aperture in the bottom of the sheath forming a pressure seal, the cartridge/skate assembly is driven along the rail to a Station where system control commands a generic material delivery Head to mate with the top of the cartridge forming a pressure seal around the variable area deposition aperture located on the top of the cartridge sheath, a layer formation environment may be maintained, roll to roll feeding and uptake of the flexible substrate is enabled via axle hub mounted bi-directional rotation drives, device layer formation proceeds as the flexible substrate is fed across the cold-plate portion of a thermoelectric heat-sink mounted on the top of the skate and so may be maintained at a desired film formation temperature, layer formation continues from bolt end to bolt end as the exposed substrate is safely rolled while passing through substrate sensitive auto-adjusting guides located on the end walls of each cylindrical cartridge lobe, once a layer is fully grown, system control flushes the pressure vessel formed by the coupling of the cartridge, skate and head and declares said pressure vessel contaminant free, the skate/cartridge assembly decouples from the head and aligns with the next material delivery head, the process continues invoking as many heads and stations as required for device layer formation until a device is fully grown and encapsulated, at that point the cartridge is uncoupled from the skate which returns to system start, the cartridge containing the as grown device is environmentally sealed, and routed to it's appropriate dock. 2) the component of claim 1, the Cartridge: A pressure enabled container consisting of two parallel, adjacent cylindrical lobes joined by a continuous web, this web forms a hollow sheath, axles or spindles for the support of roll to roll action required for depositions on the flexible substrate are concentrically mounted in the capping end wall of each lobe, each axle has hub mounted electromechanical drives or hub mounted gear couplings for mechanical axle drives providing bi-directional rotation of each axle, substrate sensitive auto-adjusting guides are mounted on the cartridge door and capping end wall of each lobe, a variable surface area deposition aperture is integral to the top web of the cartridge, a fixed area aperture is integral to the bottom web, these apertures are parallel and coaxial, a pressure resistant door is present for loading, unloading of substrate or completed device bolts respectively, a variety of process and quality control elements complete the component. 3) the component of claim 1, the Head: A generic material delivery enclosure with a telescoping hollow stem, said stem imposes a sealing force about the deposition aperture on the top of the cartridge and is a material supply and process and quality control conduit. 4) the component of claim 1, the Skate: A transporter and power transfer unit that may carry a self regulating thermoelectric heat sink, when coupled with a cartridge a pressure seal results. 5) the component of claim 1, the Rail: The moving means for the skate/cartridge assembly from station to station and head to head, provides for power supply and recycling and is the conduit for process and quality control. 6) the component of claim 1, the Station : A radial or linear array of heads. 